Typical ultrasound transducers use piezoelectric ceramic elements coupled to acoustic impedance matching layers. The impedance matching layers can improve transmission of ultrasound energy into a medium, thereby improving the efficiency of the transducer. Previously, matching layers have been fabricated directly on the piezoelectric ceramic elements, followed by machining or other altering of the matching layers to obtain a desired matching layer thickness. Further, to obtain a stack of matching layers, some prior methods repeat the foregoing process iteratively with different matching layer materials.
Unfortunately, such a fabrication method can be labor intensive and/or expensive. In addition, air entrapped in one or more matching layers formed in this manner can result in undesired electrical contact between one or more components of the transducer and a medium in contact with the transducer, such as the body of a patient. Moreover, some materials used to form impedance matching layers are mechanically weak and thus prone to damage over time. Further, prior methods of making a transducer result in the formation of joints, seams or interfaces between transducer components. Such joints or seams can exhibit debonding or delamination over time, resulting in degradation of device performance and/or electrical contact between the transducer and a medium in physical contact with the transducer. Therefore, improved ultrasound transducers and methods of making ultrasound transducers are needed.